Earlier quoted context omitted.
It looks like you have to purchase a license to use it. The only price quoted on the page is $2999 -- a bit steep for some illustrations on a blog. Please explain.
I believe the $2999 price is for licensing Zwibbler so you can have it on your own site/app. For example if you had a company that made custom t-shirts, users could create their own designs using Zwibbler on your site. On the other hand, if you just want to draw some pictures using the Zwibbler demo to put them on your blog, you don't need a license, and it doesn't cost you anything.
Re: Show HN: RoughJS – Create hand-drawn graphics using JavaScript
#101That is the sensible interpretation but it's not very clear from the wording on the page. I like being in the clear, legally speaking.